Treating glaucoma, cardiovascular diseases, and renal diseases

ABSTRACT

This document provides methods and materials related to treating glaucoma, ocular hypertension, cardiovascular diseases, and renal diseases. For example, this document provides isolated nucleic acid molecules and viral vectors (e.g., lentiviral vectors) containing isolated nucleic acid molecules. Methods for reducing intraocular pressure as well as symptoms and progression of cardiovascular and renal diseases also are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Ser. No. 12/298,431, filed Aug. 6, 2009, which is a National Stage application under 35 U.S.C. §371 and claims benefit of International Application No. PCT/US2007/067710 having an International Filing Date of Apr. 27, 2007, which claims the benefit of priority of U.S. Provisional Application No. 60/795,789 having a filing date of Apr. 28, 2006. The disclosures of the prior applications are considered part of (and are incorporated by reference in) the disclosure of this application.

STATEMENT AS TO FEDERALLY SPONSORED RESEARCH

This invention was made with government support under grant EY014411/ILP#17, awarded by the National Institutes of Health. The government has certain rights in the invention.

BACKGROUND

1. Technical Field

This document relates to methods and materials involved in treating glaucoma, cardiovascular diseases, and renal diseases. For example, this document relates to methods and materials that can be used to reduce intraocular pressure.

2. Background Information

Glaucoma is characterized by a loss of visual function due to damage to the optic nerve. The several morphologically or functionally distinct types of glaucoma are typically characterized by elevated intraocular pressure, which is considered to be causally related to the pathological course of the disease. Ocular hypertension is a condition where intraocular pressure is elevated but no apparent loss of visual function has occurred. Such patients are considered to be at high risk for the eventual development of the visual loss associated with glaucoma. If glaucoma or ocular hypertension is detected early and treated promptly with medications that effectively reduce elevated intraocular pressure, loss of visual function or its progressive deterioration can generally be ameliorated. Drug therapies that have proven to be effective for the reduction of intraocular pressure include both agents that decrease aqueous humor production and agents that increase the outflow facility.

SUMMARY

This document provides methods and materials related to treating glaucoma, ocular hypertension, cardiovascular diseases, and renal diseases. For example, this document provides isolated nucleic acid molecules encoding a polypeptide having COX-2 activity as well as isolated nucleic acid molecules encoding a polypeptide having prostaglandin F_(2α) receptor activity. In addition, this document provides viral vectors (e.g., lentiviral vectors) containing nucleic acid encoding a polypeptide having COX-2 activity, a polypeptide having prostaglandin F_(2α) receptor activity, a polypeptide having prostacyclin IP receptor activity, a polypeptide having prostaglandin synthase activity, a polypeptide having prostacyclin synthase activity, or combinations thereof Such isolated nucleic acid molecules and viral vectors can be used to reduce intraocular pressure and to treat cardiovascular and renal diseases. For example, viral vectors provided herein can be administered to the eye or eyes of a human patient having elevated intraocular pressure, thereby reducing the patient's risk of developing glaucoma. Viral vectors provided herein also can be administered to the heart of a human patient having cardiovascular disease, thereby reducing the patient's risk of having a myocardial infarction. In some cases, viral vectors provided herein can be administered to the kidneys of a human patient having renal disease, thereby reducing the patient's risk of having renal failure.

This document also provides methods and materials for reducing intraocular pressure. For example, the methods provided herein can include administering a viral vector such as a lentiviral vector to one or both eyes. Such methods can be used to treat existing glaucoma or can be used to slow or prevent the onset of glaucoma. In some cases, the methods and materials provided herein can be used to reduce a human patient's risk of developing glaucoma. In some cases, the methods and materials provided herein can be used to increase a mammal's ability to respond to an intraocular pressure reducing treatment such as Latanoprost (xalatan) eye drops.

This document also provides methods and materials for treating cardiovascular and renal diseases. For example, the methods provided herein can include administering a viral vector systemically, administering a viral vector to the heart (e.g., via a catheter), or administering a viral vector to one or both kidneys (e.g., via a urethral catheter or during dialysis). Such methods can be used to reduce the severity of a symptom of a cardiovascular or renal disease (e.g., hypertension or renal fibrosis) and can be used to reduce the progression of a cardiovascular or renal disease (e.g., to reduce progressive loss of function of the heart or kidneys).

In general, one aspect of this document features a method for treating a mammal having glaucoma or elevated intraocular pressure. The method comprises, or consists essentially of, administering a nucleic acid to an eye of the mammal under conditions effective to reduce intraocular pressure of the eye, wherein the nucleic acid comprises a nucleic acid sequence encoding a polypeptide having cyclooxygenase-2 activity and a nucleic acid sequence encoding a polypeptide having prostaglandin F_(2α) receptor activity. The nucleic acid can be administered to said eye using a viral vector (e.g., a lentiviral vector).

In another aspect of this document features a method for treating a mammal having glaucoma or elevated intraocular pressure. The method comprises, or consists essentially of, administering a viral vector to an eye of the mammal under conditions effective to reduce intraocular pressure of the eye, where the viral vector comprises a nucleic acid encoding a polypeptide having cyclooxygenase-2 activity. The mammal can be a human. The viral vector can be a lentiviral vector. The administering step can comprise contacting the eye with a solution containing the viral vector. The solution can be a saline solution or a physiologically acceptable buffered solution. The solution can comprise between 10³ and 10¹² lentivirus particles per mL (e.g., between 10⁴ and 10¹¹ lentivirus particles per mL; between 10⁵ and 10¹⁰ lentivirus particles per mL; between 10⁶ and 10¹⁰ lentivirus particles per mL; or between 10⁶ and 10⁹ lentivirus particles per mL). The nucleic acid can be a template for an mRNA molecule encoding the polypeptide, where the mRNA has an increased stability in cells as compared to the stability of an mRNA molecule transcribed from the sequence set forth in SEQ ID NO:2. The nucleic acid can comprise a nucleic acid sequence that encodes the same amino acid sequence as set forth in SEQ ID NO:1 and can comprise a codon sequence different than the codons set forth in SEQ ID NO:2. The nucleic acid sequence can comprise five or more different codon sequences compared to the codon sequences set forth in SEQ ID NO:2. The nucleic acid can comprise the sequence set forth in SEQ ID NO:3. The polypeptide can comprise the sequence set forth in SEQ ID NO:1. The viral vector can comprise a nucleic acid sequence encoding a polypeptide having prostaglandin F_(2α) receptor activity. The nucleic acid sequence encoding the polypeptide having prostaglandin F_(2α) receptor activity can be a template for an mRNA molecule encoding the polypeptide having prostaglandin F_(2α) receptor activity, where the mRNA has an increased stability in cells as compared to the stability of an mRNA molecule transcribed from the sequence set forth in SEQ ID NO:5. The nucleic acid sequence encoding the polypeptide having prostaglandin F_(2α) receptor activity can comprise a nucleic acid sequence that encodes the same amino acid sequence as set forth in SEQ ID NO:4 and can comprise a codon sequence different than the codons set forth in SEQ ID NO:5. The nucleic acid sequence encoding the polypeptide having prostaglandin F_(2α) receptor activity can comprise five or more different codon sequences compared to the codon sequences set forth in SEQ ID NO:5. The nucleic acid sequence encoding the polypeptide having prostaglandin F_(2α) receptor activity can comprise the sequence set forth in SEQ ID NO:6. The polypeptide having prostaglandin F_(2α) receptor activity can comprise the sequence set forth in SEQ ID NO:4. The viral vector can comprise a nucleic acid sequence encoding a polypeptide having prostaglandin synthase activity. The nucleic acid sequence encoding the polypeptide having prostaglandin synthase activity can comprise the sequence set forth in SEQ ID NO:8. The polypeptide having prostaglandin synthase activity can comprise the sequence set forth in SEQ ID NO:7. The viral vector can comprise nucleic acid encoding a polypeptide having prostaglandin F_(2α) receptor activity and a polypeptide having prostaglandin synthase activity. The method can be effective to reduce the intraocular pressure by at least 10 percent. The method can be effective to reduce the intraocular pressure by at least 20 percent. The method can be effective to reduce the intraocular pressure by at least 30 percent. The viral vector can be a feline immunodeficiency virus vector.

In another aspect, this document features a method for treating a mammal having a cardiovascular or renal disease. The method comprises, or consists essentially of, administering a viral vector to the mammal under conditions effective to reduce the severity of a symptom of the cardiovascular or renal disease, where the viral vector comprises a nucleic acid encoding a polypeptide having cyclooxygenase-2 activity. The mammal can be a human. The viral vector can be a lentiviral vector. The nucleic acid can be a template for an mRNA molecule encoding the polypeptide, where the mRNA has an increased stability in cells as compared to the stability of an mRNA molecule transcribed from the sequence set forth in SEQ ID NO:2. The nucleic acid can comprise a nucleic acid sequence that encodes the same amino acid sequence as set forth in SEQ ID NO:1 and can comprise a codon sequence different than the codons set forth in SEQ ID NO:2. The nucleic acid sequence can comprise five or more different codon sequences compared to the codon sequences set forth in SEQ ID NO:2. The nucleic acid can comprise the sequence set forth in SEQ ID NO:3. The polypeptide can comprise the sequence set forth in SEQ ID NO:1. The viral vector can comprise a nucleic acid sequence encoding a polypeptide having prostacyclin IP receptor activity. The nucleic acid can comprise a nucleic acid sequence that encodes the same amino acid sequence as set forth in SEQ ID NO:9 and can comprise a codon sequence different than the codons set forth in SEQ ID NO:10. The nucleic acid sequence encoding the polypeptide having prostacyclin IP receptor activity can comprise the sequence set forth in SEQ ID NO:10. The polypeptide having prostacyclin IP receptor activity can comprise the sequence set forth in SEQ ID NO:9. The viral vector can comprise a nucleic acid sequence encoding a polypeptide having prostacyclin synthase activity. The nucleic acid sequence encoding the polypeptide having prostacyclin synthase activity can comprise the sequence set forth in SEQ ID NO:12. The polypeptide having prostacyclin synthase activity can comprise the sequence set forth in SEQ ID NO:11. The viral vector can comprise nucleic acid encoding two or more polypeptides selected from the group consisting of a polypeptide having cyclooxygenase-2 activity, a polypeptide having prostacyclin IP receptor activity, and a polypeptide having prostacyclin synthase activity. The symptom can be reduced by 25%. The symptom can be reduced by 50%. The symptom can be reduced by 75%. The symptom can be reduced by 100%.

In another aspect, this document features a viral vector comprising a nucleic acid encoding a polypeptide having cyclooxygenase-2 activity. The viral vector can be a lentiviral vector. The nucleic acid can be a template for an mRNA molecule encoding the polypeptide, where the mRNA has an increased stability in cells as compared to the stability of an mRNA molecule transcribed from the sequence set forth in SEQ ID NO:2. The nucleic acid can comprise a nucleic acid sequence that encodes the same amino acid sequence as set forth in SEQ ID NO:1 and can comprise a codon sequence different than the codons set forth in SEQ ID NO:2. The nucleic acid sequence can comprise five or more different codon sequences compared to the codon sequences set forth in SEQ ID NO:2. The nucleic acid can comprise the sequence set forth in SEQ ID NO:3. The polypeptide can comprise the sequence set forth in SEQ ID NO:1. The viral vector can comprise a nucleic acid sequence encoding a polypeptide having prostaglandin F_(2α) receptor activity. The nucleic acid sequence encoding the polypeptide having prostaglandin F_(2α) receptor activity can be a template for an mRNA molecule encoding the polypeptide having prostaglandin F_(2α) receptor activity, where the mRNA has an increased stability in cells as compared to the stability of an mRNA molecule transcribed from the sequence set forth in SEQ ID NO:5. The nucleic acid sequence encoding the polypeptide having prostaglandin F_(2α) receptor activity can comprise a nucleic acid sequence that encodes the same amino acid sequence as set forth in SEQ ID NO:4 and can comprise a codon sequence different than the codons set forth in SEQ ID NO:5. The nucleic acid sequence encoding the polypeptide having prostaglandin F_(2α) receptor activity can comprise five or more different codon sequences compared to the codon sequences set forth in SEQ ID NO:5. The nucleic acid sequence encoding the polypeptide having prostaglandin F_(2α) receptor activity can comprise the sequence set forth in SEQ ID NO:6. The polypeptide having prostaglandin F_(2α) receptor activity can comprise the sequence set forth in SEQ ID NO:4. The viral vector can comprise a nucleic acid sequence encoding a polypeptide having prostaglandin synthase activity. The nucleic acid sequence encoding the polypeptide having prostaglandin synthase activity can comprise the sequence set forth in SEQ ID NO:8. The polypeptide having prostaglandin synthase activity can comprise the sequence set forth in SEQ ID NO:7. The viral vector can comprise nucleic acid encoding a polypeptide having prostaglandin F_(2α) receptor activity and a polypeptide having prostaglandin synthase activity. The viral vector can comprise nucleic acid encoding a polypeptide having prostacyclin IP receptor activity. The nucleic acid can comprise a nucleic acid sequence that encodes the same amino acid sequence as set forth in SEQ ID NO:9 and can comprise a codon sequence different than the codons set forth in SEQ ID NO:10. The nucleic acid sequence encoding the polypeptide having prostacyclin IP receptor activity can comprise the sequence set forth in SEQ ID NO:10. The polypeptide having prostacyclin IP receptor activity can comprise the sequence set forth in SEQ ID NO:9. The viral vector of claim 45, where the viral vector comprises a nucleic acid sequence encoding a polypeptide having prostacyclin synthase activity. The nucleic acid sequence encoding the polypeptide having prostacyclin synthase activity can comprise the sequence set forth in SEQ ID NO:12. The polypeptide having prostacyclin synthase activity can comprise the sequence set forth in SEQ ID NO:11. The viral vector can comprise nucleic acid encoding two or more polypeptides selected from the group consisting of a polypeptide having cyclooxygenase-2 activity, a polypeptide having prostacyclin IP receptor activity, and a polypeptide having prostacyclin synthase activity.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used to practice the invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF THE DRAWINGS

FIG. 1 contains graphs plotting the percent base composition versus base position in the human COX-2 mRNA (Upper panel), the coding region of the human COX-2 mRNA (middle panel), and the codon-optimized COX-2 cDNA (lower panel).

FIG. 2 contains photomicrographs of cells transfected with transfer constructs containing the wild-type COX-2 cDNA (COX2igWF) or the codon-optimized COX-2 cDNA (XOGWF) upstream of an IRES operably linked to a GFP coding sequence. Cells transfected with a transfer construct containing a GFP coding sequence operably linked to a CMV promoter (GINWF) served as a positive control, and mock transfected cells served as a negative control.

FIG. 3 is a Northern blot analyzing expression of COX-2 mRNA in cells transfected with a transfer construct containing the codon-optimized (XOGWF) or wild-type (COX2igWF) COX-2 cDNA. Cells transfected with a transfer construct containing a GFP coding sequence operably linked to a CMV promoter (GINWF) served as a positive control, and mock transfected cells served as a negative control.

FIG. 4 is a Western blot analyzing expression of COX-2 polypeptides in 293T cells transfected with a transfer construct containing a codon-optimized or wild-type COX-2 cDNA.

FIG. 5 is a schematic diagram of FIV-based lentiviral transfer constructs containing a codon-optimized COX-2 cDNA (pXOGWF), a PGF synthase cDNA (pPGFSigWF), or a codon-optimized prostaglandin F receptor cDNA (pHAFPRigWF). The prostaglandin F receptor cDNA was HA-tagged to enable detection of prostaglandin F receptor polypeptides on Western blots

FIG. 6 is a Western blot analyzing expression of prostaglandin F receptor (FPR), COX-2, and prostaglandin F synthase (PGFS) polypeptides in cells that were mock transfected or transfected with one or more lentiviral transfer vectors containing a cDNA encoding an FPR, COX-2, or PGFS polypeptide.

FIG. 7 is a graph plotting levels of PGF2alpha in 293T cells transfected with a construct containing a COX-2 cDNA, in 293T cells transfected with a construct containing a PGF synthase (PGFS) cDNA, and in 293T cells co-transfected with a construct containing a COX-2 cDNA and a construct containing a PGFS cDNA. FIG. 7 also contains Western blots analyzing expression of COX-2 and PGFS polypeptides in the transfected 293T cells.

FIG. 8 is a chart indicating the therapeutic regimen applied to each subject in the animal study.

FIG. 9 contains a series of graphs plotting intraocular pressure (mm Hg) versus days post injection for the indicated treatment groups.

FIG. 10 is a graph plotting the mean intraocular pressure (IOP) sustained for more than two months in each of the five experimental groups described in FIG. 8 and in eyes treated with the control vector. The p-values were determined using a paired, two-tailed distribution T-test.

FIG. 11 is a listing of an amino acid sequence (SEQ ID NO:1) of a human COX-2 polypeptide.

FIG. 12 is a listing of a wild-type human nucleic acid sequence (SEQ ID NO:2) encoding the amino acid sequence set forth in SEQ ID NO:1.

FIG. 13 is a listing of a codon optimized nucleic acid sequence (SEQ ID NO:3) encoding the amino acid sequence set forth in SEQ ID NO:1. The bold, underlined nucleotides represent nucleotides that were changed relative to the sequence set forth in SEQ ID NO:2.

FIG. 14 is a listing of an amino acid sequence (SEQ ID NO:4) of a human prostaglandin F_(2α) receptor polypeptide containing an HA tag. The underlined amino acid sequence represents the HA tag.

FIG. 15 is a listing of a wild-type human nucleic acid sequence (SEQ ID NO:5) encoding the amino acid sequence set forth in SEQ ID NO:4.

FIG. 16 is a listing of a codon optimized nucleic acid sequence (SEQ ID NO:6) encoding the amino acid sequence set forth in SEQ ID NO:4. The bold, underlined nucleotides represent nucleotides that were changed relative to the sequence set forth in SEQ ID NO:5.

FIG. 17 is a listing of an amino acid sequence (SEQ ID NO:7) of a human prostaglandin F synthase polypeptide.

FIG. 18 is a listing of a nucleic acid sequence (SEQ ID NO:8) encoding a human prostaglandin F synthase polypeptide.

DETAILED DESCRIPTION

This document provides methods and materials related to treating glaucoma, intraocular hypertension, cardiovascular disease, and renal disease. For example, this document provides isolated nucleic acid molecules encoding a polypeptide having COX-2 activity as well as isolated nucleic acid molecules encoding a polypeptide having prostaglandin F_(2α) receptor activity. This document also provides viral vectors (e.g., lentiviral vectors) containing a polypeptide having COX-2 activity, a polypeptide having prostaglandin F_(2α) receptor activity, a polypeptide having prostacyclin IP receptor activity, a polypeptide having prostaglandin synthase activity, a polypeptide having prostacyclin synthase activity, or combinations thereof

In addition, this document provides methods and materials for reducing intraocular pressure. For example, the methods provided herein can include administering a viral vector such as a lentiviral vector to one or both eyes. Such methods can be used to treat existing glaucoma or can be used to slow or prevent the onset of glaucoma. In some cases, the methods and materials provided herein can be used to reduce a human patient's risk of developing glaucoma.

This document also provides methods and materials for treating cardiovascular diseases (e.g., pulmonary hypertension) and renal diseases (e.g., diabetic nephropathy). For example, the methods provided herein can include administering a viral vector systemically, administering a viral vector to the heart, or administering a viral vector to one or both kidneys. Such methods can be used to reduce the severity of a symptom of a cardiovascular or renal disease (e.g., hypertension or renal fibrosis) and can be used to reduce the progression of a cardiovascular or renal disease (e.g., to reduce progressive loss of function of the heart or kidneys).

The term “nucleic acid” as used herein encompasses both RNA and DNA, including cDNA, genomic DNA, and synthetic (e.g., chemically synthesized) DNA. The nucleic acid can be double-stranded or single-stranded. Where single-stranded, the nucleic acid can be the sense strand or the antisense strand. In addition, nucleic acid can be circular or linear.

The term “isolated” as used herein with reference to nucleic acid refers to a naturally-occurring nucleic acid that is not immediately contiguous with both of the sequences with which it is immediately contiguous (one on the 5′ end and one on the 3′ end) in the naturally-occurring genome of the organism from which it is derived. For example, an isolated nucleic acid can be, without limitation, a recombinant DNA molecule of any length, provided one of the nucleic acid sequences normally found immediately flanking that recombinant DNA molecule in a naturally-occurring genome is removed or absent. Thus, an isolated nucleic acid includes, without limitation, a recombinant DNA that exists as a separate molecule (e.g., a cDNA or a genomic DNA fragment produced by PCR or restriction endonuclease treatment) independent of other sequences as well as recombinant DNA that is incorporated into a vector, an autonomously replicating plasmid, a virus (e.g., a retrovirus, adenovirus, or herpes virus), or into the genomic DNA of a prokaryote or eukaryote. In addition, an isolated nucleic acid can include a recombinant DNA molecule that is part of a hybrid or fusion nucleic acid sequence.

The term “isolated” as used herein with reference to nucleic acid also includes any non-naturally-occurring nucleic acid since non-naturally-occurring nucleic acid sequences are not found in nature and do not have immediately contiguous sequences in a naturally-occurring genome. For example, non-naturally-occurring nucleic acid such as an engineered nucleic acid is considered to be isolated nucleic acid. Engineered nucleic acid can be made using common molecular cloning or chemical nucleic acid synthesis techniques. Isolated non-naturally-occurring nucleic acid can be independent of other sequences, or incorporated into a vector, an autonomously replicating plasmid, a virus (e.g., a retrovirus, adenovirus, or herpes virus), or the genomic DNA of a prokaryote or eukaryote. In addition, a non-naturally-occurring nucleic acid can include a nucleic acid molecule that is part of a hybrid or fusion nucleic acid sequence.

It will be apparent to those of skill in the art that a nucleic acid existing among hundreds to millions of other nucleic acid molecules within, for example, cDNA or genomic libraries, or gel slices containing a genomic DNA restriction digest is not to be considered an isolated nucleic acid.

An isolated nucleic acid molecule provided herein can contain a nucleic acid sequence encoding a polypeptide having COX-2 activity, a polypeptide having prostaglandin F_(2α) receptor activity, a polypeptide having prostacyclin IP receptor activity, a polypeptide having prostaglandin synthase activity, a polypeptide having prostacyclin synthase activity, or combinations thereof Non-limiting examples of nucleic acid sequences encoding a polypeptide having COX-2 activity, a polypeptide having prostaglandin F2α receptor activity, a polypeptide having prostacyclin IP receptor activity, a polypeptide having prostaglandin synthase activity, and a polypeptide having prostacyclin synthase activity are set forth in SEQ ID NO:2, SEQ ID NO:5, SEQ ID NO:10 (GenBank® GI Number GI:39995095), SEQ ID NO:8, and SEQ ID NO:12 (GenBank® GI Number GI:75517290), respectively. Non-limiting examples of amino acid sequences of polypeptides having COX-2 activity, prostaglandin F2α receptor activity, prostacyclin IP receptor activity, prostaglandin synthase activity, and prostacyclin synthase activity are set forth in SEQ ID NO:1, SEQ ID NO:4, SEQ ID NO:9 (GenBank® GI Number GI:4506263), SEQ ID NO:7, and SEQ ID NO:11 (GenBank® GI Number GI:2493373), respectively.

Isolated nucleic acid molecules provided herein can contain a sequence that has one or more codons that are different from those found in a wild-type sequence. For example, an isolated nucleic acid molecule provided herein can contain a nucleic acid sequence that encodes a polypeptide having COX-2 activity that is identical to a human COX-2 polypeptide with the nucleic acid sequence having one or more codons that are different from wild-type human nucleic acid encoding that human COX-2 polypeptide. An example of such a nucleic acid molecule is provided in FIG. 13.

Any method can be used to obtain an isolated nucleic acid molecule provided herein including, without limitation, common molecular cloning and chemical nucleic acid synthesis techniques. For example, PCR can be used to obtain an isolated nucleic acid molecule containing a nucleic acid sequence set forth in FIG. 12. In some cases, the obtained nucleic acid can be mutated to form a codon-optimized sequence such as the sequence set forth in FIG. 13.

Any of the nucleic acid molecules provided herein can be incorporated into a viral vector. For example, a viral vector can be designed to contain an isolated nucleic acid molecule having a nucleic acid sequence encoding a polypeptide having COX-2 activity, a polypeptide having prostaglandin F2α receptor activity, a polypeptide having prostacyclin IP receptor activity, a polypeptide having prostaglandin synthase activity, a polypeptide having prostacyclin synthase activity, or combinations thereof Examples of viral vectors that can be used include, without limitation, lentiviral vectors (e.g., feline immunodeficiency viral vectors), retroviral vectors (e.g., murine retroviral vectors), foamy virus vectors, adenovirus vectors, adeno-associated virus vectors, vaccinia virus vectors, and herpes virus vectors. Viral vectors can be replication incompetent and can contain few if any viral genes. In some cases, the isolated nucleic acid molecules provided herein can used as naked DNA or can be incorporated into plasmids, transposons, retroelement-based vectors, or phage integrase containing DNA vectors.

This document provides methods for treating glaucoma or intraocular hypertension. Such methods can include administering an isolated nucleic acid molecule provided herein to a mammal in need of treatment (e.g., a human, dog, cat, horse, cow, pig, or monkey). Any method can be used to administer an isolated nucleic acid molecule provided herein. For example, a viral vector provided herein can be administered to a mammal via oral administration or direct administration to one or both eyes. In some cases, a viral vector provided herein can be contained within a solution that can be directly applied to an eye. Any method can be used to administer such a solution to an eye. For example, a solution containing a viral vector provided herein can be administered in a manner similar to the manner used to self administer eye drops.

As described herein, this document provides methods and materials for treating cardiovascular and renal diseases. Cardiovascular diseases include, without limitation, pulmonary hypertension (e.g., pulmonary arteriolar hypertension), arterial thrombosis, myocardial ischemia, myocardial infarction, atherosclerosis, restenosis, and reperfusion injury. Examples of renal diseases include, without limitation, diabetic nephropathy, progressive renal disease, renal fibrosis, renal hypertrophy, and glomerulosclerosis. As described herein, a mammal having a cardiovascular or renal disease can be treated using an isolated nucleic acid molecule provided herein (e.g., an isolated nucleic acid molecule encoding a polypeptide having cyclooxygenase-2 activity, a polypeptide having prostacyclin IP receptor activity, a polypeptide having prostacyclin synthase activity, or any combination thereof). A viral vector containing an isolated nucleic acid molecule provided herein can be used to administer the nucleic acid to a mammal in need of treatment. Viral vectors can be prepared using standard materials (e.g., packaging cell lines and vectors) and methods known to those of ordinary skill in the art.

Viral vectors containing one or more nucleic acid molecules provided herein (e.g., one or more of a nucleic acid encoding a polypeptide having cyclooxygenase-2 activity, a nucleic acid encoding a polypeptide having prostacyclin IP receptor activity, and a nucleic acid encoding a polypeptide having prostacyclin synthase activity) can be administered to a mammal having a cardiovascular or renal disease via numerous routes. For example, a viral vector can be administered systemically (e.g., via intravenous injection). In some cases, a viral vector can be administered directly to the heart. Direct administration of a viral vector to the heart can be achieved using a catheter or a stent, for example, and can performed during a therapeutic manipulation such as arterial bypass surgery. In some cases, a viral vector can be administered directly to one or both kidneys. Various methods can be used to deliver a viral vector to a kidney. For example, a urethral catheter can be used to deliver a viral vector to a kidney. In some cases, a viral vector can be delivered to a kidney during dialysis or by direct injection into the kidney (e.g., CT-guided direct needle injection into the kidney). In some cases, a viral vector can be targeted to the heart or kidneys using liposomes or by expressing a polypeptide on the surface of the viral particle that interacts with another polypeptide that is expressed predominantly or selectively on the surface of heart or kidney cells. In some cases, one or more nucleic acid molecules provided herein can be administered to a mammal having cardiovascular or renal disease by direct injection of the naked nucleic acid molecules into the heart or kidney, or by direct administration of liposomes containing the nucleic acid molecules. As with viral vectors, liposomes also can be targeted to heart or kidney tissue. Viral vectors, naked nucleic acids, and liposomes can be administered to a mammal in a biologically compatible solution or a pharmaceutically acceptable delivery vehicle. Suitable pharmaceutical formulations depend in part on the use and route of delivery. For example, a suitable formulation for direct injection is isotonic and has a neutral pH.

After identifying a mammal as having glaucoma, intraocular hypertension, a cardiovascular disease, or a renal disease, the mammal can be administered a viral vector containing a nucleic acid disclosed herein. A viral vector can be administered to a mammal in any amount, at any frequency, and for any duration effective to achieve a desired outcome (e.g., to reduce the severity of a symptom of glaucoma, cardiovascular disease, or renal disease). In some cases, a viral vector can be administered to a mammal having glaucoma, intraocular hypertension, a cardiovascular disease, or a renal disease to reduce the severity of a symptom or to reduce the progression rate of the condition by 5, 10, 25, 50, 75, 100, or more percent. For example, the severity of a symptom can be reduced in a mammal such that the symptom is no longer detected by the mammal In some cases, the progression of a condition can be reduced such that no additional progression is detected. Any method can be used to determine whether or not the severity of a symptom or the progression rate of a condition is reduced. For example, a mammal having glaucoma can be tested for intraocular pressure before and after treatment to determine whether the pressure is reduced. In some cases, a mammal can be observed or tested for the severity of a symptom of cardiovascular disease (e.g., high blood pressure, blood clots in arteries and veins, pain isolated to one leg (usually the calf or medial thigh), swelling in the extremity, or varicose veins) before and after treatment to determine whether or not the severity of a symptom is reduced. In some cases, renal biopsy tissue taken from a mammal before and after treatment can be analyzed (e.g., for fibrosis) to determine whether the severity of a symptom is reduced. To determine whether or not progression of a condition (e.g., glaucoma, intraocular hypertension, cardiovascular disease, or renal disease) is reduced, a physical examination can be performed at different time points to determine the stage or severity of the condition. The stage or severity of the condition observed at different time points can be compared to assess the progression rate. After treatment as described herein, the progression rate can be determined again over another time interval to determine whether or not the progression rate has decreased. For example, renal function can be assessed at various time points to determine whether the function is improving, worsening, or staying the same.

An effective amount of a viral vector can be any amount that reduces the severity of a symptom or the progression of a condition (e.g., glaucoma, intraocular hypertension, cardiovascular disease, or renal disease) without producing significant toxicity to the mammal If a particular mammal fails to respond to a particular amount, then the amount of the viral vector can be increased by, for example, two fold. After receiving this higher concentration, the mammal can be monitored for both responsiveness to the treatment and toxicity symptoms, and adjustments made accordingly. The effective amount can remain constant or can be adjusted as a sliding scale or variable dose depending on the mammal's response to treatment. Various factors can influence the actual effective amount used for a particular application. For example, the frequency of administration, duration of treatment, use of multiple treatment agents, route of administration, immunocompetency of the mammal, and severity of the condition may require an increase or decrease in the actual effective amount administered.

The frequency of administration can be any frequency that reduces the severity of a symptom or progression rate of a condition without producing significant toxicity to the mammal For example, the frequency of administration can be from about once in a lifetime to about once a month. The frequency of administration can remain constant or can be variable during the duration of treatment. A course of treatment with a viral vector can include rest periods. For example, a viral vector can be administered over a six month period followed by a three month rest period, and such a regimen can be repeated multiple times. As with the effective amount, various factors can influence the actual frequency of administration used for a particular application. For example, the effective amount, duration of treatment, use of multiple treatment agents, route of administration, immunocompetency of the mammal, and severity of the condition may require an increase or decrease in administration frequency.

An effective duration for administering a viral vector provided herein can be any duration that reduces the severity of a symptom or the progression rate of glaucoma, intraocular hypertension, cardiovascular disease, or renal disease without producing significant toxicity to the mammal Thus, the effective duration can vary from several days to several weeks, months, or years. In general, the effective duration for the treatment of glaucoma, intraocular hypertension, cardiovascular disease, or renal disease can range in duration from several months to several years. In some cases, an effective duration can be for as long as an individual mammal is alive. Multiple factors can influence the actual effective duration used for a particular treatment. For example, an effective duration can vary with the frequency of administration, effective amount, use of multiple treatment agents, route of administration, immunocompetency of the mammal, and severity of the condition.

The invention will be further described in the following examples, which do not limit the scope of the invention described in the claims.

EXAMPLES Example 1 Modulation of Prostaglandin Pathways Reduces Intraocular Pressure

Experiments were conducted to determine whether expression of polypeptides involved in prostaglandin biosynthetic and response pathways can be manipulated to provide a sustained improvement in intraocular pressure involved in diseases such as glaucoma.

Methods and Materials Cloning FIV-Based Transfer Construct Plasmids

pCOX2igWF: A plasmid having the normal human COX-2 cDNA (obtained from S. Prescott, Huntsman Cancer Institute) was NotI-XbaI-digested to isolate the COX-2 cDNA and blunted with T4 polymerase. pGiNWF (Loewen et al., Investig. Ophthalmol. Vis. Sci., 43:3686-3690 (2002)) was digested with AgeI and EcoRI, and blunted with T4 polymerase to isolate the backbone sequence that was then ligated with the COX-2 cDNA insert. Next, an IRES (internal ribosome entry site)-GFP cassette was blunt-end ligated into the EcoRI site just downstream of COX-2. This insertion resulted in a bicistronic FIV-based transfer construct with COX-2 expression driven by the CMV promoter and GFP expression being driven by the IRES just downstream of the COX-2 cDNA cassette. This plasmid, COX2igWF, was the basis for the cloning of the following transfer constructs.

pXOGWF: A codon-optimized human COX-2 cDNA was designed and synthesized with the assistance of GenScript Corporation custom services (Scotch Plains, N.J.). Codon usage was optimized for usage in mammalian cells. G-C content was optimized, and other factors such as secondary structure and repetitive codons were taken into consideration to achieve codon optimization. The codon-optimized COX-2 cDNA was designed to include flanking restriction sites to enable downstream recombinant cloning strategies. BamHI sites flank the codon-optimized COX-2 gene, and these sites were used to insert the optimized cDNA into the BamHI-digested backbone of COX2igWF. This essentially replaced the wild-type COX-2 cDNA cassette with the codon-optimized COX-2 cDNA.

pGFSigWF: The PGFS cDNA from hPGFS-cDNA pUC8 (obtained from Kikuko Watanabe, University of East Asia, Japan) was removed by EcoRI and SalI digestion, and blunted with T4 DNA polymerase. This cDNA insert was blunt ligated into the BamHI-digested backbone of COX2igWF.

pHAFPRigWF: An HA-tagged prostaglandin F receptor (HAFPR) cDNA plasmid (obtained from G. FitzGerald, University of Pennsylvania, USA), HA-FP, contains the HAFPR cDNA flanked by an upstream KpnI and a downstream NcoI site. The HAFPR cassette was removed by KpnI-NcoI digestion, blunted with T4 DNA polymerase and ligated with T4 DNA ligase into the BamHI-digested backbone of COX2igWF.

pcoFPRigWF: A codon-optimized human HA-tagged FPR cDNA was designed and synthesized with the assistance of GenScript Corporation custom services (Scotch Plains, N.J.). Codon usage was optimized for usage in mammalian cells. G-C content was optimized, and other factors such as secondary structure and repetitive codons were taken into consideration to achieve codon optimization. The codon-optimized HAFPR was designed to include flanking restriction sites for accessible cloning strategies. BamHI sites flank the codon-optimized HAFPR gene and were used to digest and ligate into the BamHI-digested backbone of COX2igWF.

PGF2alpha Assay

293T cells in 6 well plates were transfected with 2 μg XOGWF or PGFSigWF using the calcium phosphate transfection method as described elsewhere (Loewen et al., Methods Mol. Biol., 229:251-271 (2003)). Media was changed 12 to 16 hours later and collected 24 hours thereafter. Media was filtered (0.2 μm) to remove cells and used in the Prostaglandin F2 a enzyme immunoassay kit (Cayman Chemical, cat. no. 516011) as recommended by the manufacturer's protocol manual.

Northern Blot

293T cells were transfected with equivalent quantities of COX2igWF, XOWGF, or GINWF. Cells were treated with 1 mL Trizol 36 hours post-transfection and stored at −80° C. until RNA purification. Trizol-treated lysates were treated with chloroform, followed by isopropanol, and spun to isolate nucleic acid. Nucleic acid was treated with DNase, followed by RNA extraction with equal volume of phenol:chloroform:isoamyl alcohol (125:24:1). RNA was precipitated with 1/10 volume 3M sodium acetate and 2.5 volumes 100% ethanol.

Isolated total cellular RNA was separated by gel electrophoresis (1.2% agarose gel, 3.75% formaldehyde, 1× MOPS). After gel electrophoresis, RNA was transferred onto a nylon transfer membrane (Nytran Supercharge Membrane, Schleicher & Schuell, cat. no. 10416284).

A beta-actin anti-sense oligo probe was 5′-end labeled using T4 PNK (Promega) and [γ-³²P]ATP incubated at 37° C. for 30 minutes followed by heat inactivation at 70° C. for 10 minutes. Labeled primer probe was purified using a quick spin column and hybridized with RNA on nylon membrane overnight at 42° C. The membrane was washed and then exposed to MR X-ray film (Kodak) at −80° C. for five days and developed.

Since all transfer constructs contain the GFP gene cassette to be included in the message, mRNA expression levels for each message were assessed by probing for GFP sequence common to all messages in this experiment.

25 ng of GFP anti-sense oligo probe was randomly labeled using dNTP stock solution, 50 μCi α-dCTP and Klenow. The random labeling reaction occurred at 37° C. for 1 hour and was heat-inactivated at 65° C. for 10 minutes. Random labeled probe was purified using a quick spin column followed by hybridization with the RNA-containing nylon membrane for 5 hours to 3 days at −80° C. The membrane was exposed to MR X-ray film (Kodak) and developed.

Western Blot

For Western blotting, cells were lysed in Tris-buffered saline containing 1% Triton X-100 and 1% NP-40, plus a protease inhibitor cocktail (Complete-mini; Boehringer). Lysates were centrifuged to remove chromatin. Proteins were resolved in sodium dodecyl sulfate-10% polyacrylamide gels and transferred to Immobilon P membranes (Millipore). Blocked membranes were incubated overnight at 4° C. or for 2 hours at room temperature with mouse anti-COX-2 MAb (Cayman Chemical, cat. no. 160112), rat anti-HA MAb (Roche), or rabbit anti-hPGFS Ab (obtained from Kikuko Watanabe), diluted in Tris-buffered saline-5% nonfat milk plus 0.05% Tween 20. After washing, membranes were incubated with the appropriate horseradish peroxidase-tagged secondary antibody. Bound antibodies were detected by ECL (Amersham Pharmacia Biotech).

Vector Production and Titration

Transfections were performed using the calcium phosphate transient transfection method in ten-chamber cell factories (CF10) as described elsewhere (Loewen et al., Methods Mol. Biol., 229:251-271 (2003)). Medium was changed 12 to 16 hours later, and supernatants were collected 48 hours thereafter, filtered through a 0.2-μm-pore-size filter, and concentrated by two rounds of ultracentrifugation. The first spin was performed in a series of 250 mL polyallomer Oakridge ultracentrifuge bottles (Sorvall, cat. no. 54477) at 19,000 rpm in a SureSpin 630 rotor (Sorvall, cat. no. 79367) in a Sorvall Discovery 100SE ultracentrifuge (67,000 g_(rmax)) for 6 hours at 4° C. Supernatant was removed, and vector was resupended in 30 mL PBS and centrifuged over a sucrose cushion in a swinging bucket SW41TI rotor at 24,000 rpm for 2 hours at 4° C., and aliquoted and frozen at −80° C.

CrFK cells were transduced with serial dilutions of each vector preparation. 48 hours after transduction, cells were harvested, and titers of each vector preparation were determined by flow cytometry for GFP expression. All preparations were tested for reverse transcriptase (RT) activity as described elsewhere (Saenz et al., J. Virol., 79(24):15175-88 (2005)).

Vector Administration to Cat Anterior Chamber

Experiments were conducted in pathogen-free domestic cats (Harlan, Indianapolis, Ind.). Prior to vector administration, cats were anesthetized with 10 mg/kg intramuscular tiletamine HCl/zolazepam HCl (Telazol; Fort Dodge Laboratories Inc., Fort Dodge, Iowa) injection. Anterior chambers of feline eyes were transcorneally injected with a bolus of 200 μL PBS containing 10⁷ TU of vectors GINWF, XOGWF, PGFSigWF, or HAFPRigWF. Animals receiving two or more different vectors received a total of 2×10⁷ TU and 3×10⁷ TU vector, respectively.

Intraocular Pressure Measurements, Slit Lamp Examinations, & Gonioscopic Observation

Prior to examinations, cats were anesthetized with 10 mg/kg intramuscular tiletamine HCl/zolazepam HCl (Telazol; Fort Dodge Laboratories Inc., Fort Dodge, Iowa) injection. Weekly examinations consisted of slit lamp (Haag-Streit, Mason, Ohio) observation and determination of intraocular pressure using a handheld pneumatonometer (Model 30 Classic; Medtronic, Fridley, Minn.).

Fluorescence of transduced™ was observed with a standard gonioscope (Posner; Ocular Instruments, Bellevue, Wash.) and a microscope (Eclipse E400; Nikon) equipped with a GFP-optimized filter (EF-4 B-2E/C FITC, cat. no. 96107; Nikon).

Results

Codon Optimization of Prostaglandin Pathway mRNAs

Initial studies revealed that human COX-2 and PGF receptor polypeptides were difficult to express using standard methods. By performing in silico analyses, it was discovered that the coding regions of both the COX-2 and PGF receptor mRNAs were aberrantly AU-rich, with a markedly suboptimal codon bias. The skewed codon use of the human COX-2 coding region is very similar in composition to that of lentiviral structural genes. This composition makes lentiviral mRNAs labile, a problem that the viruses overcome with specialized viral polypeptides that stabilize RNA at particular stages of the life cycle. The composition of the prostaglandin pathway mRNAs presumably fosters rapid endogenous turnover. Human codon-optimized versions of the human COX-2 cDNA (FIG. 1) and the PGF receptor cDNA were synthesized. The codon-optimized COX-2 cDNA contains a GC-rich sequence that encodes an amino acid sequence identical to the wild-type COX-2 sequence.

Transfer constructs were generated that contained the wild-type or the codon-optimized COX-2 cDNA upstream of an IRES operably linked to a GFP coding sequence. Cells were transfected with the constructs, and GFP expression levels were observed. A significantly higher level of GFP expression was observed in cells transfected with the construct containing the codon-optimized COX-2 cDNA (XOGWF) as compared to cells transfected with the construct containing the wild-type COX-2 cDNA (COX2igWF; FIG. 2).

Cells transfected with the transfer constructs containing the wild-type or codon-optimized COX-2 cDNA were also analyzed for mRNA levels by Northern blotting. The blots were analyzed with a GFP probe random-labeled using ³²P-dCTP. The blots were also analyzed with a β-actin probe 5′-labeled using ³²P-dATP to control for equal loading. The level of mRNA was much higher in cells transfected with the construct containing the codon-optimized COX-2 cDNA than in cells transfected with the construct containing the wild-type COX-2 cDNA (FIG. 3).

Recombinant DNA constructs containing the codon-optimized COX-2 cDNA or the wild-type COX-2 cDNA were also used to transfect 293T cells, and lysates from the transfected cells were analyzed for COX-2 expression by Western blotting. Expression of COX-2 polypeptides was higher in cells transfected with the construct containing the codon-optimized COX-2 cDNA than in cells transfected with the construct containing the wild-type COX-2 cDNA (FIG. 4).

These results indicate that codon optimization of the COX-2 coding region increases the stability of the transcribed RNA, resulting in increased expression at the polypeptide level. The wild-type COX-2 coding region, not just the 3′ untranslated region as was previously recognized, prevents significant polypeptide expression. In contrast, PGF synthase does not have an aberrant RNA base composition and does not require codon optimization.

Effect of the Expression of Prostaglandin Pathway Polypeptides on IOP In Vivo

Lentiviral transfer constructs based on the feline immunodeficiency virus (FIV) vector system (Poeschla et al., Nat. Med., 4(3):354-7 (1998)) were generated which contained a human codon-optimized COX-2 cDNA, a human PGF synthase cDNA, or a human codon-optimized PGF receptor cDNA (FIG. 5). Levels of COX-2, PGF synthase, and PGF receptor polypeptides in cells transfected with one or more of the transfer constructs were analyzed by Western blotting, and expression of each of the polypeptides was detected (FIG. 6).

Production of PGF2alpha was measured in 293T cells transfected with a construct containing a COX-2 or a PGF synthase (PGFS) cDNA, and in 293T cells co-transfected with a construct containing a COX-2 cDNA and a construct containing a PGF synthase cDNA. Production of PGF2alpha was observed in the presence of COX-2 polypeptides and correlated strongly with the expression level of COX-2 polypeptides (FIG. 7). Co-expression of COX-2 and PGFS resulted in an even greater level of PGF2alpha production than expression of COX-2 alone (FIG. 7). Synthesis of PGF2alpha was increased up to 0.9×10⁴-fold in the transfected cells relative to synthesis of PGF2alpha in control cells. Expression of PGFS alone did not increase PGF2alpha levels, indicating that COX-2 is a rate-limiting polypeptide in the prostaglandin synthesis pathway.

The effect of expression of prostaglandin pathway polypeptides on intraocular pressure (IOP) was investigated in a large animal model developed for glaucoma studies and described elsewhere (Loewen et al., Invest. Ophthalmol. Vis. Sci., 43(12):3686-90 (2002)). Fifteen domestic cats were divided into five groups, with three cats in each group. The anterior chamber of the right eye of each cat was injected with one or more lentiviral vectors containing a COX-2, PGFS, or prostaglandin F receptor (FPR) cDNA. The anterior chamber of the left eye of each cat was injected with 10⁷-10⁸ TU of a control eGFP vector (FIG. 8). The animals were monitored serially for intraocular pressure (IOP) and clinical effects.

The lentiviral vectors were well-tolerated in the animals and produced marked, sustained (two months at present, with observation of all animals ongoing), and highly significant IOP decreases (the mean over the entire two months was 4.2 mm Hg, p<0.002) compared to the IOP levels in eyes treated with the control vector. A combination of vectors containing COX-2 and PGF receptor cDNAs produced the largest IOP decrease (mean=5.6 mm Hg, 38% reduction, p<5×10⁻¹⁴; FIGS. 9 and 10).

These results indicate that major prostaglandin biosynthetic and response pathways can be manipulated. Codon optimization of the COX-2 coding region profoundly augments mRNA stability. Sustained, substantial, highly statistically significant decreases in IOP were achieved in a large animal model.

OTHER EMBODIMENTS

It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims. 

1. A method for treating a mammal having glaucoma or elevated intraocular pressure, said method comprising administering nucleic acid encoding a polypeptide having cyclooxygenase-2 activity and nucleic acid encoding a polypeptide having prostaglandin F_(2α) receptor activity to an eye of said mammal under conditions effective to reduce intraocular pressure of said eye by at least 10 percent.
 2. The method of claim 1, wherein said mammal is a human.
 3. The method of claim 1, wherein said administering step comprises contacting said eye with a solution containing said nucleic acid encoding said polypeptide having cyclooxygenase-2 activity and said nucleic acid encoding said polypeptide having prostaglandin F_(2α) receptor activity.
 4. The method of claim 1, wherein said method is effective to reduce said intraocular pressure by at least 20 percent.
 5. The method of claim 1, wherein said method is effective to reduce said intraocular pressure by at least 30 percent.
 6. The method of claim 1, wherein said nucleic acid encoding said polypeptide having cyclooxygenase-2 activity is administered using a viral vector.
 7. The method of claim 6, wherein said viral vector is a lentiviral vector.
 8. The method of claim 1, wherein said nucleic acid encoding said polypeptide having prostaglandin F_(2α) receptor activity is administered using a viral vector.
 9. The method of claim 8, wherein said viral vector is a lentiviral vector.
 10. The method of claim 1, wherein said nucleic acid encoding said polypeptide having cyclooxygenase-2 activity and said nucleic acid encoding said polypeptide having prostaglandin F2α receptor activity are administered using a viral vector.
 11. The method of claim 10, wherein said viral vector is a lentiviral vector.
 12. The method of claim 1, wherein said polypeptide having cyclooxygenase-2 activity is a human cyclooxygenase-2 polypeptide, and wherein said nucleic acid encoding said polypeptide having cyclooxygenase-2 activity is codon-optimized for use in mammalian cells.
 13. The method of claim 1, wherein said polypeptide having prostaglandin F_(2α) receptor activity is a human prostaglandin F_(2α) receptor polypeptide, and wherein said nucleic acid encoding said polypeptide having prostaglandin F_(2α) receptor activity is codon-optimized for use in mammalian cells. 